<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * PDO PostgreSQL Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package        CodeIgniter
 * @subpackage    Drivers
 * @category    Database
 * @author        EllisLab Dev Team
 * @link        https://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver
{

    /**
     * Sub-driver
     *
     * @var    string
     */
    public $subdriver = 'pgsql';

    /**
     * Database schema
     *
     * @var    string
     */
    public $schema = 'public';

    // --------------------------------------------------------------------

    /**
     * ORDER BY random keyword
     *
     * @var    array
     */
    protected $_random_keyword = array('RANDOM()', 'RANDOM()');

    // --------------------------------------------------------------------

    /**
     * Class constructor
     *
     * Builds the DSN if not already set.
     *
     * @param    array $params
     * @return    void
     */
    public function __construct($params)
    {
        parent::__construct($params);

        if (empty($this->dsn)) {
            $this->dsn = 'pgsql:host=' . (empty($this->hostname) ? '127.0.0.1' : $this->hostname);

            empty($this->port) OR $this->dsn .= ';port=' . $this->port;
            empty($this->database) OR $this->dsn .= ';dbname=' . $this->database;

            if (!empty($this->username)) {
                $this->dsn .= ';username=' . $this->username;
                empty($this->password) OR $this->dsn .= ';password=' . $this->password;
            }
        }
    }

    // --------------------------------------------------------------------

    /**
     * Database connection
     *
     * @param    bool $persistent
     * @return    object
     */
    public function db_connect($persistent = FALSE)
    {
        $this->conn_id = parent::db_connect($persistent);

        if (is_object($this->conn_id) && !empty($this->schema)) {
            $this->simple_query('SET search_path TO ' . $this->schema . ',public');
        }

        return $this->conn_id;
    }

    // --------------------------------------------------------------------

    /**
     * Insert ID
     *
     * @param    string $name
     * @return    int
     */
    public function insert_id($name = NULL)
    {
        if ($name === NULL && version_compare($this->version(), '8.1', '>=')) {
            $query = $this->query('SELECT LASTVAL() AS ins_id');
            $query = $query->row();
            return $query->ins_id;
        }

        return $this->conn_id->lastInsertId($name);
    }

    // --------------------------------------------------------------------

    /**
     * Determines if a query is a "write" type.
     *
     * @param    string    An SQL query string
     * @return    bool
     */
    public function is_write_type($sql)
    {
        if (preg_match('#^(INSERT|UPDATE).*RETURNING\s.+(\,\s?.+)*$#is', $sql)) {
            return FALSE;
        }

        return parent::is_write_type($sql);
    }

    // --------------------------------------------------------------------

    /**
     * "Smart" Escape String
     *
     * Escapes data based on type
     *
     * @param    string $str
     * @return    mixed
     */
    public function escape($str)
    {
        if (is_bool($str)) {
            return ($str) ? 'TRUE' : 'FALSE';
        }

        return parent::escape($str);
    }

    // --------------------------------------------------------------------

    /**
     * ORDER BY
     *
     * @param    string $orderby
     * @param    string $direction ASC, DESC or RANDOM
     * @param    bool $escape
     * @return    object
     */
    public function order_by($orderby, $direction = '', $escape = NULL)
    {
        $direction = strtoupper(trim($direction));
        if ($direction === 'RANDOM') {
            if (!is_float($orderby) && ctype_digit((string)$orderby)) {
                $orderby = ($orderby > 1)
                    ? (float)'0.' . $orderby
                    : (float)$orderby;
            }

            if (is_float($orderby)) {
                $this->simple_query('SET SEED ' . $orderby);
            }

            $orderby = $this->_random_keyword[0];
            $direction = '';
            $escape = FALSE;
        }

        return parent::order_by($orderby, $direction, $escape);
    }

    // --------------------------------------------------------------------

    /**
     * Show table query
     *
     * Generates a platform-specific query string so that the table names can be fetched
     *
     * @param    bool $prefix_limit
     * @return    string
     */
    protected function _list_tables($prefix_limit = FALSE)
    {
        $sql = 'SELECT "table_name" FROM "information_schema"."tables" WHERE "table_schema" = \'' . $this->schema . "'";

        if ($prefix_limit === TRUE && $this->dbprefix !== '') {
            return $sql . ' AND "table_name" LIKE \''
            . $this->escape_like_str($this->dbprefix) . "%' "
            . sprintf($this->_like_escape_str, $this->_like_escape_chr);
        }

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * List column query
     *
     * Generates a platform-specific query string so that the column names can be fetched
     *
     * @param    string $table
     * @return    string
     */
    protected function _list_columns($table = '')
    {
        return 'SELECT "column_name"
			FROM "information_schema"."columns"
			WHERE LOWER("table_name") = ' . $this->escape(strtolower($table));
    }

    // --------------------------------------------------------------------

    /**
     * Returns an object with field data
     *
     * @param    string $table
     * @return    array
     */
    public function field_data($table)
    {
        $sql = 'SELECT "column_name", "data_type", "character_maximum_length", "numeric_precision", "column_default"
			FROM "information_schema"."columns"
			WHERE LOWER("table_name") = ' . $this->escape(strtolower($table));

        if (($query = $this->query($sql)) === FALSE) {
            return FALSE;
        }
        $query = $query->result_object();

        $retval = array();
        for ($i = 0, $c = count($query); $i < $c; $i++) {
            $retval[$i] = new stdClass();
            $retval[$i]->name = $query[$i]->column_name;
            $retval[$i]->type = $query[$i]->data_type;
            $retval[$i]->max_length = ($query[$i]->character_maximum_length > 0) ? $query[$i]->character_maximum_length : $query[$i]->numeric_precision;
            $retval[$i]->default = $query[$i]->column_default;
        }

        return $retval;
    }

    // --------------------------------------------------------------------

    /**
     * Update statement
     *
     * Generates a platform-specific update string from the supplied data
     *
     * @param    string $table
     * @param    array $values
     * @return    string
     */
    protected function _update($table, $values)
    {
        $this->qb_limit = FALSE;
        $this->qb_orderby = array();
        return parent::_update($table, $values);
    }

    // --------------------------------------------------------------------

    /**
     * Update_Batch statement
     *
     * Generates a platform-specific batch update string from the supplied data
     *
     * @param    string $table Table name
     * @param    array $values Update data
     * @param    string $index WHERE key
     * @return    string
     */
    protected function _update_batch($table, $values, $index)
    {
        $ids = array();
        foreach ($values as $key => $val) {
            $ids[] = $val[$index];

            foreach (array_keys($val) as $field) {
                if ($field !== $index) {
                    $final[$field][] = 'WHEN ' . $val[$index] . ' THEN ' . $val[$field];
                }
            }
        }

        $cases = '';
        foreach ($final as $k => $v) {
            $cases .= $k . ' = (CASE ' . $index . "\n"
                . implode("\n", $v) . "\n"
                . 'ELSE ' . $k . ' END), ';
        }

        $this->where($index . ' IN(' . implode(',', $ids) . ')', NULL, FALSE);

        return 'UPDATE ' . $table . ' SET ' . substr($cases, 0, -2) . $this->_compile_wh('qb_where');
    }

    // --------------------------------------------------------------------

    /**
     * Delete statement
     *
     * Generates a platform-specific delete string from the supplied data
     *
     * @param    string $table
     * @return    string
     */
    protected function _delete($table)
    {
        $this->qb_limit = FALSE;
        return parent::_delete($table);
    }

    // --------------------------------------------------------------------

    /**
     * LIMIT
     *
     * Generates a platform-specific LIMIT clause
     *
     * @param    string $sql SQL Query
     * @return    string
     */
    protected function _limit($sql)
    {
        return $sql . ' LIMIT ' . $this->qb_limit . ($this->qb_offset ? ' OFFSET ' . $this->qb_offset : '');
    }

}
